matthias meissner is an agricultural expert at world wide fund for nature, points out that enormous tractsof land are needed for biofuels. matthias meissner: c02 emissions increase when forests and other natural habitats are turned into farmland. it doesn't matter whether the crop is sugar cane, wheat or corn. the major problem comes with the changes that occur and the release of carbon dioxide. reporter: the eu has reacted accordingly. new guidelines call for biofuels to make up no more than seven percent of combined production by 2017. emphasis is now being put on electric vehicles. the united states is by far the world's largest ethanol producer. a biofuel plan was put into action years ago and the percentage of its mix in gasoline rises steadily. nearly half of all domestic corn production winds up in ethanol. and 15% of gasoline comes from renewable sources. the state of iowa is a major producer of biofuels, and the industry has created tens of thousands of jobs. brazil has turned to sugarcane to fill its gas tanks. the south american nation is the second largest producer and the seco